(1) Field of the Invention
This invention pertains to the conversion of hydrocarbons, especially the dehydrogenation of dehydrogenatable hydrocarbons, in the presence of a heterogeneous catalyst composite. Dehydrogenatable hydrocarbons contain at least two non-aromatic adjacent carbon atoms having one or two carbon-carbon bonds in common, each carbon atom of the pair having at least one hydrogen atom bonded to it. A heterogeneous catalyst is one which is in a phase different from the phase or phases of the reactants it catalyzes, for example, a solid catalyst which catalyzes liquid or gaseous reactants.
Dehydrogenating hydrocarbons is an important commercial process because of the great demand for dehydrogenated hydrocarbons for the manufacture of various chemical products such as detergents, high octane gasolines, pharmaceutical products, plastics, synthetic rubbers, and other products well known to those skilled in the art. One example of this process is dehydrogenating normal paraffin hydrocarbons having 2 to 20 or more carbon atoms per molecule to selectively produce corresponding normal mono-olefins. These normal mono-olefins are important to the detergent industry, for example, where they are utilized to alkylate an aromatic compound such as benzene with subsequent transformation of the product arylalkane into compounds for use in a wide variety of biodegradable household and industrial detergents.
(2) Description of the Prior Art
Many components have been added to platinum group-containing compositions to obtain catalysts with improved performance. For example, U.S. Pat. Nos. 2,814,599 and 2,914,464 disclose adding primary activating agents selected from the group of gallium, indium, scandium, yttrium, lanthanum, thallium and actinium, and optional secondary activating agents selected from the group of mercury, zinc and cadmium, as well as optional promoting agents selected from the alcohols and ketones to obtain a platinum and/or palladium catalyst with improved reforming activity.
U.S. Pat. No. 3,745,112 discloses that tin is a good promoter for platinum group-containing reforming catalysts. This patent discloses also that a platinum-tin-alkali or alkaline earth composite is a particularly effective catalyst for dehydrogenating hydrocarbons. In the dehydrogenation catalyst composite of this patent the alkali or alkaline earth component is added and the amount of halogen is minimized in order to eliminate the isomerization and cracking reactions which occur on the acidic catalytic sites.
U.S. Pat. No. 3,892,657 discloses that indium is a good promoter for platinum group-containing reforming catalysts when the atomic ratio of indium to platinum is from about 0.1:1 to about 1:1. In column 4, lines 10-12, this patent discloses that only when the atomic ratio of indium to platinum is about 0.1 to 1.0 is the beneficial interaction of indium with platinum obtained. In column 25, lines 33-37, this patent discloses that when the atomic ratio is 1.35 or more, the beneficial effect of indium is not obtained. This patent discloses also that a Group IVA component selected from the group of germanium, tin, and lead can be added to the acidic form of the indium-containing catalysts for reforming applications. The acidic form of this catalyst, then, comprises a platinum group component, a Group IVA component, an indium component, a halogen component and a porous carrier aaterial. For dehydrogenation applications this patent discloses a catalyst comprising a platinum group component, an indium component and an alkali or alkaline earth component with the porous carrier material. No catalyst comprising indium, platinum, tin, and an alkali or alkaline earth component is specifically disclosed in this patent.
British Pat. No. 1 499 297 discloses a dehydrogenation catalyst comprising platinum, at least one of the elements gallium, indium and thallium, and an alkali metal, especially lithium or potassium, with alumina as the carrier material. The disclosure of this patent is not limited to any specific atomic ratio of gallium or indium or thallium to platinum. No catalyst comprising tin is disclosed.